Want an exercise program that helps you work out smarter, not harder? You've found it. The Women's Health+ Ultimate HIIT ...

Download a printable calendar here This ... to turn your treadmill stroll into a HIIT workout. >>Get the 20-minute interval ...

A good rule of thumb: you should not be able to talk and work out simultaneously during a well-programmed HIIT workout. Here's an example of a basic HIIT rowing workout. Total time: 12 min.